Historically, projection engines of projection systems have been designed employing high intensity discharge lamps. These prior art projection engines/systems suffer from a number of disadvantages. For example, the lamps typically have relatively short lives and reduced brightness after an initial period of usage. Further, there is an appreciable period of waiting for the lamp to warm up, when a projection engine/system is first turned on. During that period, either no image is available or the available images are of poor quality. Additionally, active cooling arrangements are typically required to dissipate the heat created during operation.
Resultantly, there has been a lot of interest in developing and manufacturing in a mass scale projection engines and projection systems employing solid state light sources. Such engines/systems typically either do not have or have the aforementioned disadvantages in a lesser degree.
FIG. 1 illustrates a simplified plane view of a typical solid state light source and micromirror light valve based projection system architecture. The plane view may be a top view or a side view of the projection system. As illustrated, solid state light source based projection system 100 includes a number of constituent colored solid state light sources, such as LEDs 102, 104, and 106 sourcing green (G), red (R), and blue (B) lights respectively. LEDs 102, 104, and 106 are arranged in an orthogonal manner, respectively disposed on three sides of dichroic combiner 108. Dichroic combiner 108 is employed to combine the lights emitted by LEDs 102, 104, and 106. Further, light integrator 110 is placed in the optical path to enhance the combined light. Mirror 112 is employed to reflect the enhanced light onto micromirror device 114. In various embodiments one or more relay lenses (not shown) may also be employed to focus light from the integrator 110 onto micromirror device 114.
Micromirror device 114 includes a number of micromirrors that may be individually tilted to an “on” or an “off” position to selectively reflect the enhanced light reflected from mirror 112 towards projection lens 116 (“on”) or away from projection lens 116 (“off”). Resultantly, with each micromirror corresponding to a pixel, and by selectively controlling their positions, an image or a series of images, including a series of images forming a motion picture, may be projected.
While the architecture of FIG. 1 works well, it is nevertheless desirable to further improve on reducing the cost and/or increasing reliability of the next generation of projection engines and projection systems.